Theresa May last night claimed she 'always has and always will put Britain's national security first'

Mrs May said: “As Prime Minister I always have and always will put Britain’s national security first.

“That is why if elected on June 8 I will ensure that the UK continues to spend at least two per cent of GDP on defence and that the budget rises every year.

"Under my leadership, the Conservatives will ensure the brave men and women of our Armed Forces have the equipment and resources they need to keep our country safe — and that we meet our obligations to the world.”

Mrs May promised that under her leadership, the Tories 'will ensure the brave men and women of our Armed Forces have the equipment and resources they need'

Mr Corbyn’s credentials on security faced fresh criticism when a video from 2011 emerged of him slamming Nato.

Speaking at a peace conference in Portugal, he said: “I think it’s perfectly right to call for the abolition of nuclear weapons, for the reduction in arms expenditure and end this nonsense of Nato’s right to intervene anywhere around the world.”

The Labour boss has previously called for Nato to “shut up shop”.

And his close aides have questioned recent troop movements to the Balkan states to protect them from renewed Russian aggression.